Epsilon Aquilae

66 L ☉

Deneb el okab Borealis is the proper name of the star ε Aquilae ( Epsilon Aquilae ) in the constellation Aquila. The star Zeta Aquilae distinction is made with the proper name Deneb el okab Australis from Epsilon Aquilae. The two stars together form the tail feathers of the eagle, so they were together as " Deneb el okab " (Arabic ذنب العقاب, DMG ḏanab al - ʿ uqāb, tail of the eagle ') respectively. Because Epsilon Aquilae is the more northerly of the two stars, it the additional Borealis (Latin boreas = "North" ) is enclosed.

Epsilon Aquilae is a red giant of spectral type K1 and has an apparent magnitude of 4.03 mag. Its distance is about 154 light-years. He is a so-called Bariumstern, that is its atmosphere is above average highly enriched in barium and other heavy elements. Such stars are born, when they absorb that matter, which is repelled by a close companion in the course of its development, during this ends up as a white dwarf companion.

Epsilon Aquilae actually is a multiple star. At a distance of only about 3.5 AE a companion of unknown type should circumambulate in 1270 days him. In addition, Epsilon Aquilae could have two other companions. One component is a luminous faint star with an apparent brightness of 10.2 mag and is 148.6 arc seconds or about 3700 AU from the central star away. In the second (possible) companion who likes 10.1 is bright, there are two differing information (66 or 131 seconds of arc ) on his distance from the primary star. However, these two faint components may only optical double star.